Revert "Attributes on K&R C functions should not cause incompatible..."

...function type with a redeclaration having the same attribute. Fixing this
introduced a secondary problem where we were assuming that K&R functions
could not be attributed types when reporting old-style function definitions
that are not preceded by a prototype."

Also Revert "Hopefully fixes a compile error introduced by r294861."

This reverts commit r294862, r294861, as they bork the ARM builds and
haven't fix it back.

Also, please, short commit titles, long commit decsriptions...

llvm-svn: 294910

clang/include/clang/AST/Type.h

@@ -1888,13 +1888,6 @@ public:
   /// immediately following this class.
   template <typename T> const T *getAs() const;
 
-  /// Member-template getAsAdjusted<specific type>. Look through specific kinds
-  /// of sugar (parens, attributes, etc) for an instance of \<specific type>.
-  /// This is used when you need to walk over sugar nodes that represent some
-  /// kind of type adjustment from a type that was written as a \<specific type>
-  /// to another type that is still canonically a \<specific type>.
-  template <typename T> const T *getAsAdjusted() const;
-
   /// A variant of getAs<> for array types which silently discards
   /// qualifiers from the outermost type.
   const ArrayType *getAsArrayTypeUnsafe() const;
@@ -6015,38 +6008,6 @@ template <typename T> const T *Type::getAs() const {
   return cast<T>(getUnqualifiedDesugaredType());
 }
 
-template <typename T> const T *Type::getAsAdjusted() const {
-  static_assert(!TypeIsArrayType<T>::value, "ArrayType cannot be used with getAsAdjusted!");
-
-  // If this is directly a T type, return it.
-  if (const T *Ty = dyn_cast<T>(this))
-    return Ty;
-
-  // If the canonical form of this type isn't the right kind, reject it.
-  if (!isa<T>(CanonicalType))
-    return nullptr;
-
-  // Strip off type adjustments that do not modify the underlying nature of the
-  // type.
-  const Type *Ty = this;
-  while (Ty) {
-    if (const auto *A = dyn_cast<AttributedType>(Ty))
-      Ty = A->getModifiedType().getTypePtr();
-    else if (const auto *E = dyn_cast<ElaboratedType>(Ty))
-      Ty = E->desugar().getTypePtr();
-    else if (const auto *P = dyn_cast<ParenType>(Ty))
-      Ty = P->desugar().getTypePtr();
-    else if (const auto *A = dyn_cast<AdjustedType>(Ty))
-      Ty = A->desugar().getTypePtr();
-    else
-      break;
-  }
-
-  // Just because the canonical type is correct does not mean we can use cast<>,
-  // since we may not have stripped off all the sugar down to the base type.
-  return dyn_cast<T>(Ty);
-}
-
 inline const ArrayType *Type::getAsArrayTypeUnsafe() const {
   // If this is directly an array type, return it.
   if (const ArrayType *arr = dyn_cast<ArrayType>(this))

clang/include/clang/AST/TypeLoc.h

@@ -70,13 +70,6 @@ public:
     return t;
   }
 
-  /// \brief Convert to the specified TypeLoc type, returning a null TypeLoc if
-  /// this TypeLock is not of the desired type. It will consider type
-  /// adjustments from a type that wad written as a T to another type that is
-  /// still canonically a T (ignores parens, attributes, elaborated types, etc).
-  template <typename T>
-  T getAsAdjusted() const;
-
   /// The kinds of TypeLocs.  Equivalent to the Type::TypeClass enum,
   /// except it also defines a Qualified enum that corresponds to the
   /// QualifiedLoc class.
@@ -2195,24 +2188,6 @@ public:
 
   QualType getInnerType() const { return this->getTypePtr()->getElementType(); }
 };
-
-template <typename T>
-inline T TypeLoc::getAsAdjusted() const {
-  TypeLoc Cur = *this;
-  while (!T::isKind(Cur)) {
-    if (auto PTL = Cur.getAs<ParenTypeLoc>())
-      Cur = PTL.getInnerLoc();
-    else if (auto ATL = Cur.getAs<AttributedTypeLoc>())
-      Cur = ATL.getModifiedLoc();
-    else if (auto ETL = Cur.getAs<ElaboratedTypeLoc>())
-      Cur = ETL.getNamedTypeLoc();
-    else if (auto ATL = Cur.getAs<AdjustedTypeLoc>())
-      Cur = ATL.getOriginalLoc();
-    else
-      break;
-  }
-  return Cur.getAs<T>();
-}
 }
 
 #endif

clang/lib/Sema/SemaDecl.cpp

@@ -7564,12 +7564,11 @@ static FunctionDecl* CreateNewFunctionDecl(Sema &SemaRef, Declarator &D,
     // Determine whether the function was written with a
     // prototype. This true when:
     //   - there is a prototype in the declarator, or
-    //   - the type R of the function is some kind of typedef or other non-
-    //     attributed reference to a type name (which eventually refers to a
-    //     function type).
+    //   - the type R of the function is some kind of typedef or other reference
+    //     to a type name (which eventually refers to a function type).
     bool HasPrototype =
       (D.isFunctionDeclarator() && D.getFunctionTypeInfo().hasPrototype) ||
-      (!R->getAsAdjusted<FunctionType>() && R->isFunctionProtoType());
+      (!isa<FunctionType>(R.getTypePtr()) && R->isFunctionProtoType());
 
     NewFD = FunctionDecl::Create(SemaRef.Context, DC,
                                  D.getLocStart(), NameInfo, R,
@@ -12105,7 +12104,7 @@ Decl *Sema::ActOnFinishFunctionBody(Decl *dcl, Stmt *Body,
           !LangOpts.CPlusPlus) {
         TypeSourceInfo *TI = FD->getTypeSourceInfo();
         TypeLoc TL = TI->getTypeLoc();
-        FunctionTypeLoc FTL = TL.getAsAdjusted<FunctionTypeLoc>();
+        FunctionTypeLoc FTL = TL.castAs<FunctionTypeLoc>();
         Diag(FTL.getLParenLoc(), diag::warn_strict_prototypes) << 1;
       }
     }

clang/test/Sema/knr-def-call.c

@@ -39,9 +39,3 @@ void use_proto() {
   proto(42.1); // expected-warning{{implicit conversion from 'double' to 'int' changes value from 42.1 to 42}}
   (&proto)(42.1); // expected-warning{{implicit conversion from 'double' to 'int' changes value from 42.1 to 42}}
 }
-
-// PR31020
-void func(short d) __attribute__((cdecl)); // expected-note{{previous declaration is here}}
-void __attribute__((cdecl)) func(d)
-  short d; // expected-warning{{promoted type 'int' of K&R function parameter is not compatible with the parameter type 'short' declared in a previous prototype}}
-{}

clang/test/Sema/warn-strict-prototypes.c

@@ -60,8 +60,3 @@ void foo10(p, p2) void *p; {} // expected-warning {{old-style function definitio
 // K&R function definition with previous prototype declared is not diagnosed.
 void foo11(int p, int p2);
 void foo11(p, p2) int p; int p2; {}
-
-// PR31020
-void __attribute__((cdecl)) foo12(d) // expected-warning {{this old-style function definition is not preceded by a prototype}}
-  short d;
-{}